Drinking cups and handheld containers with leak tight top-covers, combined with dripless spout and air vent are provided throughout the years in many shapes and forms, in order to prevent spilling of the liquid, contained therein for temporarily storage. The spout and vent are provided with valves that enable fluid to be withdrawn from the container or cup, when suction is applied to the spout. The reduction in fluid content in the container is replaced by air that flows through a second opening in the cover. This air vent holds a control valve that opens when the pressure sinks below the atmospheric outside pressure, due to the suction action at the spout. As an example; a drip less feeding training container of this nature has been described by Belanger in U.S. Pat. No. 5,079,013; U.S. Pat. No. 5,542,670 by Morano; U.S. Pat. No. 5,186,347 by Freeman etc. For all these inventions the application was primarily made for babies and toddlers with the objective of eliminating spillage of the fluid by throwing over the cup or container and while drinking during movement. In the above patent descriptions other references are made to other inventors, all with the same or similar goals in mind of eliminating spillage of fluid.
The thus described applications are suitable for non-carbonized fluids and cold drinks only. If carbonized fluids are applied, the pressure in the container will built-up thereby pushing the valve open and leakage and spilling is not prevented. The same applies for hot drinking fluids, whereby the air above the fluid is heated and expands, causing the pressure in the container to rise and will push out the fluid, if not held in the upright position. Spilling could be prevented, however, by using a stronger resilient valve material in the case of Morano U.S. Pat. No. 5,542,670 or a stronger spring in the case of Belanger, U.S. Pat. No. 5,079,013. The draw back, however, is that suction to the spout has to increase appreciably, even beyond human capacity and opening of the valve would be impossible or at least cumbersome.
For beverage cans, as nowadays are commonly available to the consumer with carbonized drinking fluids, adapters are provided that clips onto the top of the can to close off the beverage can after opening and/or make drinking easier than directly from the can. Such features are provide for in the following descriptions: U.S. Pat. No. 4,796,774 by Nabinger; U.S. Pat. No. 4,852,776 by Patton; U.S. Pat. No. 4,883,192 by Krugman; U.S. Pat. No. 5,071,042 by Esposito, U.S. Pat. No. 5,947,324 by Palinchak, EP 0870 685 A1 by Igor etc. These applications have the disadvantage that the pressure is immediately released from the can after opening and in the shortest possible time the carbon dioxide is released from the fluid and becomes flat and much less attractive to drink.
This means that all previous described applications are not suitable for carbonized beverages or hot drinking fluids.
The present invention overcome all these problems as well as for beverage cans as for closed non-spilling drinking cups combining a number of advantages over prior art solutions, in the same application being: Maintaining the gas pressure to keep the fluid carbonized; easy transport of partially filled containers and no fluid is spilled while drinking and used in action. For the beverage can the present invention has an additionally advantage of being more hygienic than using a beverage can closure and/or drinking adapter as provided for in e.g. U.S. Pat. No. 4,883,192 of Krugman and other inventions thereafter.